Dispensing apparatus for liquid fuel



Nov. 5, 1957 G, w. WRIGHT ETAL. 2,812,111

DISPENSING APPARATUS FOR LIQUID FUEL 4 Sheets-Sheet 1 Filed Jan. 15, 1953 INVENTORS GEOQGE IM mun-e1,

BY JOSEPH D.CLYMEIZ and ERNEST E.JRCKSON.

Nov. 5, 1957 a. w. WRIGHT ETAL 2,312,111

DISPENSING APPARATUS FOR LIQUID FUEL Filed Jan. 15. 1953 4 Sheets-Sheet 2 By JOSEPH CL IMEE amd. 130 EENEjT E. J/TYCKSOAQ CU USU CJ ATT 2-E-/5.

Nov. 5, 1957 G. w. WRIGHT ET AL 2,812,111

DISPENSING APPARATUS FOR LIQUID FUEL Filed Jan. 15, 1953 4 Sheets-Sheet 4 I T? 104 a I 2 I 304 ff 132 I B .91: r- Pu m H Pump 5 5o 5 Control Control 4 98 v IN VEN TORS GEORGE W'WEIGHT, BY JOSEPH D. O. M152 and ERNEST E..TFICKSON,

United States Patent 2,812,111 DISPENSING APPARATUS FOR noun) FUEL Application January 15, 1953, Serial No. 331,344 16 Claims. (Cl. 222-76) This invention relates to dispensing apparatus for liquid fuel, such as gasoline, in which the fuel is pumped from a supply tank by a submcrgcd pump and delivered to one or more dispensing stands under pressure. Such a gen eral system is disclosed in u ctr-pending application filed by us and Robert J. lunch and Otto R. Scheurcr, Serial No. 186,815, filed September 26, 1950, now patent No. 2,732,l03, dated January 24, i956. The present invention comprises certain improvements over the apparatus of that co-pending application.

It is an object ol the invention to provide improved git oliuc dispensing apparatus in which a submerged pump delivers gasoline from a supply tank under pressure to a plurality of dispensing stands and in whica the apparatus may be actuated iudcpemtcntly at each such stand. It is an object of the invention to provide a multiple stand dispcnsing installation in which .1 plurality of systems may be normally operated independently, each to pump fuel under pressure from its own supply to its own dispensing stand or stands under control at its own stands, and in which, in the event of failure of the supply of one system. the stands of that system can be readily switched over and connected-to control and be supplied by the pump and supply of another system. lt is an object of the invention to provide a submergedpump dispensing system employing a vulvcless pump unit and in which the supply line leading from the supply tank to the dispensing stands is maintained full of liquid. It is an object of the invention to eliminate air and gases from such a supply line and to prevent delivery of air and gas to the metering and dispensing mechanism of the dispensing stands. Other and more specific objects of the invention will appear from the following specification and the accompanying drawings and from the claims.

In accordance with the invention, the pump is desirably part of an electric motor-pump unit of small diameter insertable in a supply tank through a standard flange thereon. The pump or motor-pump unit is in a submerged position in the supply tank and connected by a delivery pipe to a header which may be carried by the tank. The header is connected by suitable supply pipes to one or more dispensing stands and is provided with one or more check valves to maintain the supply pipes full of gasoline. Electric connections are provided by which pump operation may be controlled from each of the dispensing stands. The header check valves are urged to closed position both mechanically and by the pressure in the supply line, and open from a chamber, the top of which communicates with a restricted bleed passage lending back to the supply tank, so that upon operation of the pump, any air or gas below the check valves is discharged back to the tank belorc flow occurs to the dispensing line. A plurality of dispensing systems at a single installation are inter-connected through valves to permit each pump to supply either the stands of its own system or also the stands of an inter connected system, and switch-over apparatus is provided by which each pump is controlled either solely from its normally connected stands or from both its normally connected stands and the stands of the inter-connected system.

The accompanying drawings illustrate the invention.

In such drawings:

Fig. l is a somewhat schematic showing of a gasoline dispensing installation embodying the invention, such installation having stands A and B normally connected resp.ctively to separate supply systems but inter-connected so that all stands of both groups may be supplied from either supply system;

Fig. 2 is an axial section of shown in Fig. 1;

Fig. 3 is a vertical section of the pump supporting header cf Fig. l and its mounting;

Fig. 4 is a section taken on the line 4-4 of big. 3;

Fig. 5 is an enlarged section of one of the header check valves;

Fig. 6 is a partial section of a modified header in which air bleed is through a Syphon-priming ejector, in accordance with the disclosure of a co-pending application of one of us, Joseph D. Clymer, Serial No. 539,524, filed October 10, 1955;

Fig. 7 is an electrical diagram of control and switchover mechanism; and

Fig. 8 is a diagram of u modification which includes an automatically operated switch-over valve.

in the gasoline dispensing installation shown in Fig. l, a group of a plurality of dispensing stands A are con nected by supply lines 20 to a main line 22 which is connected through a valve 23 and a union 25 to a header 24 on a primary supply tank 26. The header 24 supports in submerged position in the tank a motor and pump unit 30, sometimes hereinafter identified as pump A. An auxiliary supply tank 32 is connected to the primary tank 26 by an open syphon line 34 extending from the bottom of the auxiliary tank 32 up through a flange opening 33, across to a flange opening 35 on the primary tank 26, and then down to the bottom of that primary tank 26. The high point of the syphon line is connected by a priming line 36 to an injector inlet 37 connected to the header 24.

The motor and pump unit 30 is carried by a supporting delivery pipe 40, and the motor of the motor-pump unit 30 is supplied with current through a conduit 42 which extends co-uxiully through the pipe 40 and leads to a junction box 44. The junction box 44 is connected through a seal fitting 46 to a pump-A control box 48, supplied with cur rent from a suitable supply line 50.

The installation shown in Fig. 1 also includes a second group of dispensing stands 13 connected by supply lines 70 to a main line 72 which is connected through a valve 73 and a union 75 to a header 74 mounted on a supply tank 76. This tank contains a submerged motor-pump unit 80, sometimes hereinafter identified as pump B. The pump and motor unit is carried by a supporting delivery pipe from the header 74, and the motor is supplied with current through a co-axial conduit 92 connected to a junction box 9-1. The junction box 94 is connected through a seal fitting 96 to a pumpB control box 98, supplied with current from the supply line 50.

The supply system comprising dispensing stands A, tanks 26 and 32, pumpA, and pump-A control box 48 may be referred to as system A, and the system comprising the corresponding B parts and tank 76 may be re lcrrcd to as system B. For optional inter-connection of the two systems A and ll, as to deliver gasoline from the tank of one system to the dispensing stands of the other or of both systems, the two main supply lines 22 and 72, beyond the valves 23 and 73, are inter-connected by a connecting line 82 containing a valve 84.

Each of the dispensing stands A and 13 includes a dis pensing line normally containing a meter 112 and a register 114 and other usual related mechanism. In addition,

the motor and pump unit the dispensing line of each stand is desirably connected to its supply line or 70 through a hydraulic valve mechanism 110 as disclosed in the aforesaid co-pending Serial No. 186,815. The dispensing line of each stand leads to and includes a dispensing hose terminating at a manually operated valved nozzle 100. A storage bracket 102 is provided for the nozzle, and has associated with it a control lever 104 which lies in depressed position when the nozzle is stored and the stand is not in operation.

Each of the stands also includes a switch box 106 containing a double-pole control switch 108 (a or 1:). Switch 108 is mechanically inter-connected to the control lever 104, for actuation to closed position by lifting of control lever 104, and for actuation to open position by depressing the control lever 104 either manually or by the act of hanging the nozzle 100 on the bracket 102. The stand controls thus operate in the same way as conventional gasoline dispensing stands, in a manner to which servicestation attendants are accustomed.

For convenient reference, the control switches of stands A are identified as switches 108-, and those of stands B as switches 108b, and all switches are shown diagrammatically outside their boxes 106.

The control switches 108-(1, of stands A, are connected to close a two-wire circuit from a supply line 120 to a control line 122--a leading to a switch-over box 124. The control switches 108-1), of stands B, are connected to close a two-wire circuit from the supply line 120 to a control line 122-b leading separately to the switch-over control box 124. The switch-over control box 124 carries a switch handle 130, and is suitably connected by wires 126 to the control boxes 48 and 98 for pumps A and B. With the switch handle 130 in its normal position-N the switches l08-a, in stands A, are operative to control only pump A in tank 26. and the control switches 10841, in stands B, are operative to control only the pump B in tank 76. Upon movement of the handle 130 counterclockwise, to position A, the switches 108-:1 and 1084), of both groups of stands, are connected for operation of pump A, and assuming that valve 84 in the inter-connecting line 82 is open, that pump A will be controlled by and will supply all stands. Likewise, by turning the control handle 130 clockwise, to position B, all stands are connected to control and to be supplied from pump B. Thus, in the event one tank runs dry, or one pump fails, all stands can be readily connected to control and be supplied from the other tank and pump, and operation of the service station can proceed in normal fashion, with all pumps operative to supply customers and without any necessity for requesting customers to move from one stand to another.

The pump and motor units and 80 shown in Fig. l are of the same construction, which is shown in Fig. 2. Each unit comprises a sealed electric-motor assembly 140 of long cylinder configuration mounted co-axially within a surrounding sleeve 142. The pump is mounted at the lower end of this assembly, and the space between the casing of the motor 140 and the sleeve 142 provides an annular delivery passage 144 leading upward from the pump. The motor shaft 146 is carried by suitable bearings within the motor assembly. The lower end plate 148 of the motor assembly is provided with a depending central collar 150 to receive a rotary shaft seal having a non-rotating seal member 152 sealed to the end plate 148 and spring pressed downward into sealing engagement with a rotating seal member 154 curried with and sealed to the motor shaft H6. Outwardly from the collar 150, the end plate 148 carries :1 depending outer wall 156, the lower end of which is received between a pair of upstanding rims 158 on the top impeller of the pump to form a sealing labyrinth between the outside delivery passage 144 and the inside space surroumling the seal 152-- 154. The space about the seal and within the outer wall 156 is vented through a side passage [60 to the exterior of the pump, and is maintained substantially at a tank pressure both while the pump is operating and while it is at rest. The area of that low pressure space has a controlling effect on the end thrust of the pump impeller cluster, and as that area is increased the normal downward thrust is reduced. The low-pressure area is made of a size to bring the thrust to a desirable low value.

The electric motor used may be a 250 volt, 6O cycle A. C. motor operating at about 3500 R. P. M. With such a motor, the pump is desirably a three stage impeller pump, having three impellers 162, 164, and 166 mounted in a cluster directly on the projecting end of the motor shaft 146. Each impeller has a central hub and a radial web which carries impeller blades 168 whose lower free edges are connected to and support a shroud 169. The impeller passages are desirably positioned to discharge in a direction having a downward component, to reduce cud thrust.

The impeller cluster is housed within a cage 170 which forms an axially extending passage 172 leading from the outlet of each impeller 166 and 1.64 to an inwardly extending passage 174 which opens to the eye of the next succeeding impeller. A similar passage I73 communieating with the outlet of the last stage impeller 162 leads to the delivery passage 144. The lower end of the cage 170 is closed by an end plate 176 having a central inlet opening 177 leading to the eye of the first stage impeller 166.

As will be seen in Fig. l, the motor and pump unit is desirably mounted in a position close to the bottom of its associated supply tank. The lower end of the pump desirably carries a baffle plate 180 spaced below the end plate 176 of the pump cage. This prevents the formation at the pump inlet of a vortex which would tend to carry to the inlet 177 sediment and water which may collect at the bottom of the tank, and ensures that liquid must enter radially as it approaches the inlet opening 177. Desirably, a screen 182 is mounted between the end plate 176 and the battle plate 180 to prevent the entrance of foreign matter to the pump.

The upper end of the motor assembly 140 carries an axially extending fitting 184 to receive the electric supply conduit 42 (or 92) through which a supply cable 187 leads to the motor. As has been noted, the upper end of the motor housing is sealed, and connections are made from the supply cable to the motor winding through hermetically sealed leads. Above such leads, the fitting 184 and conduit 42 form a scaled cable passage leading to the junction box 44 (or 9-1), and through such box to the seal fitting 46 (or 96).

Surrounding the central conduit fitting 184, there is an outer collar 188 by which the whole motor and pump unit is mounted on the supporting delivery pipe 40 (or 90). The annular space between the pipe 40 and the fitting 184 and conduit 42 forms an upwardly leading delivery passage 192 communicating with the pump delivery passage 144.

The pump 80 in the tank 76 of Fig. 1 is supported by its delivery pipe 90 from the header 74, whose construction is shown in Fig. 3. The tank 76 carries a standard tank fitting 200, into which is threaded a pipe or riser 202 of a suitable length to dispose the header at the desired level, usually in a covered pit below ground level. The upper end of such pipe 202 carries a flange 204 on which the header 74 is mounted. The pump-supporting pipe 90 and conduit 92 are of suitable length to position the pump close to the bottom of the tank 76.

The header 74 has a bottom wall 206 containing a central opening into which the pump-supporting pipe 90 is threaded. A pressure chamber 208 is formed between the bottom wall 206 and an intermediate wall 210, and such intermediate wall 210 has an upward extension 212 to pass the conduit 92 to a seal fitting 214 at the top of the header. A delivery passage 216 is formed between the intermediate wall 210 and the top wall 219 of the header, and leads to diametrically opposite outlet openings 220. As shown in the drawings, only one of such outlet openings is connected to a supply pipe, and the other is plugged, but either or both openings 220 may be used. The intermediate wall 210 carries one or more check valves opening from the pressure chamber 208 to the delivery chamber 216. As shown, there are two such valves 222 and 224. Conveniently, the valves 222 and 224 are provided as sub-assemblies comprising a flanged collar 226 forming a valve-seat at its upper edge, and a valve poppet 228 carried by a stem 230 and spring pressed to closed position against the seat by a spring 232. The valve sub-assemblies are inserted through openings in the top wall 219, onto seats formed in the intermediate wall 210, and are held in place by sleeves 234 pressed downwardly by cover plates 236. The valves 222 and 224 will maintain full of liquid both the supply lines 72 and 70 and the dispensing lines of the dispensing stands B, and in combination with the air-elimination described below avoid the necessity for any air or gas eliminator in the dispensing stands. The exclusion of air is required to prevent inaccuracies in the operation of the meter and register.

To prevent excessive pressures in the supply and dispensing lines, such as may result from temperature changes in those lines, a small pressure relief valve is provided between the delivery chamber 216 and the pressure chamber 208 of the header. As shown in Fig. 5. a pressure relief valve 238, conveniently a valve unit of the type used in pneumatic tires, is mounted in a bore extending through the stem of check valve 224.

The pump and its delivery line below the check valves 222 and 224 contain no valves, and liquid may drain therefrom when the pump is stopped, especially if the liquid level is low, and air or gas may be present in the pres sure chamber 208 when the pump starts. To prevent such air from passing to the supply line 72, and to prevent air-lock in the pump, an air bleed tube 240 is mounted in the bottom wall 206 of the header, with its upper inlet end near the top of the pressure chamber 208. The lower end of the air bleed tube 240 communicates with the space between the pump-supporting pipe 90 and the header mounting pipe 204, and through that space with the upper part of the tank 76. The passage through the air bleed tube 240 is of restricted size, sufiicient to vent air from the pressure chamber 208 at a rate which prevents the creation of dispensing pressure in that chamber 208 so long as that chamber contains air to enter the tube. In the absence of dispensing pressure to open the yieldingly closed check valves 222 and 224, those valves remain closed. When the pressure chamber 208 has been vented of air, and liquid enters the tube 240, that tube will then by-pass a small amount of liquid back to the tank, but the restricted size of the tube passage will so throttle liquid flow that no more than a negligible bypassing of liquid will occur, and full dispensing pressure will be created in the pressure chamber 208.

As has been indicated, the electrical supply conduit 92 extends co-axially up through the pump-supporting pipe 90 and through the header 74 to the seal fitting 214. It is sealed to the top wall of the header by that fitting, and its upper projecting end carries the junction box 94. For installation convenience, the junction box 94 is mounted on the conduit by a scaled swivel joint, as shown in Fig. 3. A mounting sleeve 242 is threaded on the upper end of the conduit, above a lock not 243. The lower wall of the junction box 94 forms a hub 244 which is rotatably received on the sleeve 242 and sealed thereto by a resilient annular gasket 246. The junction box 94 is electrically connected to the conduit 92 by a strap 248. Desirably, the electric supply cable 187 is clipped to the fixed sleeve 242 by a clip 247 to prevent twisting that cable within the conduit.

The header 24, in the system A which has an auxiliary tank connected to the primary tank by a syphon line,

. the same liquid level.

is shown in Fig. 6. The header 24 is identical with the header 74 described above and shown in Figs. 3-4, except that it omits the air bleed tube 240 and is equipped with a Syphon-priming ejector in accordance with the aforesaid Clymer application. The bottom wall 206' of the header 24 is formed to receive an ejector body 250 in an ejector chamber 252. The upper end of this chamber carries an ejector nozzle tube 254 aligned with and discharging through the body 250. The tube 254 communicates with the top of the pressure chamber 208' below the cheek valves (not shown), and serves as an air eliminating tube in place of the air bleed tube 240 shown in Fig. 3. The ejector chamber 252 is connected by a passage 256 to a check valve housing 258 attached to the side of the header 24. This contains an inwardly opening check valve 260, which conveniently comprises a sub-assembly identical with the check valve 222. The inlet chamber 262 below the check valve 260 communicates with the inlet 37 to which the syphon priming line 36 is connected.

The operation of the syphon system and header 24 is as follows: As with the header 74, the pressure chamber 208' and the delivery line thereto from the pump tends to drain back to the tank when the pump is at rest. Upon initial operation of the pump, it first expels any air from the pressure chamber 208' through the ejector 250 -254 t0 the space between the header mounting pipe 202 and the pump delivery pipe 40, and through that space back to the top of the tank. During this air-expelling operation, the pump builds up insuilicient pressure in the pressure chamber 208' to open the check valves of the header 24, so that no air is delivered through those check valves to the stand supply lines 20 and 22. When the air has been expelled, the ejector then offers sulficient restriction to flow that pressure promptly builds up in the pressure chamber 208' and the system is ready to supply gasoline under pressure to the stands A. A small by-pass quantity of liquid flows through the ejector, which lowers the pressure in the ejector chamber 252 and induces flow from the top of the syphon line 34 through the check valve 260 and ejector inlet passage 256. This ilow serves to prime the syphon line 34, and as gasoline is withdrawn by the pump from tank 26, syphon llow occurs from the auxiliary tank 32, and the two tanks are maintained at When the syphon line is fully primed, the ejector inlet passage 256 and ejector chamber 252 will be full of liquid and the induced ilow from the chamber 252 through the body 250 will be flow of liquid, and such induced liquid flow will have a restricting clfect on the by-pass flow from the pressure chamber 208' so that only a minimum and negligible by-pass flow will occur.

The switch-over mechanism and wiring controlled by the control handle 130 is shown diagrammatically in Fig. 7. As has already been noted and as further illustratcd in Fig. 7, the switches [08-(1, of stands A, are all connected in parallel to close a circuit from control supply line to control line [22-0, and the switches 108%, ol stands B, are similarly connected to close a circuit from the supply line 120 to a separate control line IZZ- b. The switch mechanism controlled by the handle is shown in a generally circular arrangement of twelve contacts numbered 1 to 12 and with four contact arms 300 to 303 movable by the handle 130 from a normal position shown in full lines, counter-clockwise to an A position shown in dotted lines, and clockwise to a B position shown in chain lines. The contact arms 300 and 30l are connected rcspcctively by wircs 3|0 and 311 to the two wires of the control line 122a. The contact arms 302 and 303 are respectively connected by wires 312 and 313 to the two wires of the control line 122-41. The interconnections between the several contacts 1 to 12 are shown in Fig. 7 and will be evident from the following description of the operation.

In the normal N-position of the handle 130 and switch arms 300 to 303 as shown in full lines in Fig. 7, a circuit is established from the control line 122-a, of stands A, for actuation of the pump-A control mechanism 48, as follows: from one side of line l22-a through line 310, contact arm 300, and contact 9, to line 314 leading to the pump-A control box 48, and back through line 315, contact 6, contact arm 301, and line 311 to the other side of control line 122-a. At the same time, a separate circuit is established from control line 122-b of pumps 13 for independent actuation of pump-B, as follows: from one side of line l22-b through line 312, contact arm 302, and contact 12, to line 316 leading to the pump-B control box 98, and back through line 317, contact 3, contact arm 303, and line 313, to the other side of control line 122-b.

When the handle 130 is turned counter-clockwise to position A, to carry the switch arms 300 to 303 to the dotted line positions indicated, a circuit from control line l22a to the pump-A control box 48 is established similar to that for normal operation, since the contact arms 300 and 301 then engage respectively the contacts 8 and which are connected by bridge lines 304 and 305 to the normal contacts 9 and 6. The control circuit from control line 122-12, however, is switched over and now connected to control pump A. Its contact arm 302 now engages contact 11 which is connected by bridge line 304 to line 314, and its contact arm 303 now engages contact 2 which is connected by bridge line 305 to line 315. In this setting both control lines 122-11 and l22b are connected to the pump-A control box 48, so that the switches l08a and 108b in all of the stands control pump A. Pump B is then out of operation and cannot be actuated from any of the stands.

When the switch-over handle 130 is turned clockwise to position B, to carry the contact arms 300 to 303 to the positions indicated in chain lines, all stands are connected to operate pump B. The circuit from line 122 remains effectively the same as in the normal setting, for the contact arms 302 and 303 now engage contacts 1 and 4, and these are respectively connected by bridge lines 306 and 307 to the normal contacts 12 and 3. The circuit from control line 122-a is switched over, however, so that it also controls pump B. Its contact arm 300 now engages contact 10, which is connected by bridge line 306 to line 316 leading to the pump-B control box 98, and its contact arm 301 now engages contact 7, which is connected by bridge line 307 to line 317 leading to the pump-l3 control box 98.

In the practical operation of the two-system installation shown in Fig. 1. the valve 84 in the connecting line 82 between the two systems A and B is normally closed, and the control handle 130 is normally in its N-position. Under these normal conditions, the two systems A and B are self-contained and independent. In the event tank 8 should run dry, the stands of system B can be immediately switched over to control and be supplied from system A, simply by moving the control handle 130 to its A-position and by opening the valve 84. The valve 7.5 in the line leading from pump B may also be closed, but this will not normally be necessary, since reverse flow through that valve to the tank 13 will be prevented by the check valves in the header 74. In the event the switchover is made because of some failure of pump B, however, the valve 73 in the delivery line from that pum B can be shut off, to completely isolate pump B, and L'l'- mit it to be wholly removed from service or replacement. A similar and corresponding switchover may be made to permit pump B to bc operated from all stands in the event of failure of pump A, by opening the valve 84, closing valve 23 and moving the swilch-over handle 130 to position B. It is thus possible to maintain all pumps in operative condition despite service failures of one pump or the emptying of one tank of an installation.

With the modification shown in Fig. 8, the switch-over in the event one tank runs dry is fully automatic in re sponse to movement of the switch-over handle 130. In place of the manual valve 84 in connecting line 82, a normally closed solenoid valve 84' is substituted. The solenoid 85' for the valve 84 is operated by a circuit containing a switch 132 interconnected for operation by the handle 130. With the handle 130 in normal position, the contact blade 133 of the switch 132 lies in open position, and the solenoid is then deenergized and the valve 84' is closed. When the handle 130 is moved to either its A or 13 positions, the contact arm 133 engages one of the contacts 154 to close the energizing circuit of the solenoid 85' and actuate the valve 84' to open position. The connecting pipe 82 between the A and 8 systems will then be opened, and the operative pump A or B, as determined by the switch 130 position, will supply gasoline from its supply tank to the supply lines 22 and 72 of both systems. Back flow through the non-operating pump will be prevented by the check valves in its supporting header.

The general operation of the dispensing apparatus is as follows: When the nozzle of any dispensing stand is lifted from its bracket 102 and the control lever 104 is lifted, the hydraulic valve of that stand will be actuated to dispensing position and the control switch 108 of that stand will be closed. A control circuit will be established through a control line 122 and the switch-over box 124 to the appropriate pump control box 48 or 98. This will actuate the pump control mechanism to start the pump 30 or 80 for delivery of gasoline to the operated stand. initial operation of the pump will promptly dispel any gas or air from the pressure chamber 208 in the header, and the whole line from the pump through the header, the supply pipes, and the dispensing line of the stand will be full of liquid under pressure ready for dispensing. Dispensing How will be controlled by the manually operable nozzle 100, and when that nozzle is opened, gasoline will be delivered under pressure from the tank to and through the nozzle. Upon completion of the dispensing operation, the nozzle will be hung in storage position on the bracket 102, which will depress the control lever 104, and this will open the switch 108 and set the hydraulic valve 110 to a flow-blocking position. The opening of the switch 108 will tie-energize the control circuit 122, and this will actuate the pump control mechanism to stop the pump.

A plurality of stands of the same system A and B may be operated simultaneously, for the pumps 30 and 80 have ample capacity to supply a plurality of stands. When a second stand is operated during the operation of a first stand, the closing of the second control switch 108 will maintain the control line 122 energized and will therefore maintain the pump in operation until the second dispensing operation has been completed.

The pump assembly neither includes nor requires any valves disposed within a tank. The check valves 222 and 224 in the header maintain the supply and dispensing lines full of gasoline, and are positioned at a point where they are conveniently accessible for service, and because the valves are embodied in the system as readily replaceable sub-assemblies, the servicing of those valves is simple and requires a minimum of time. The arrangement facilitates the use of a submerged motor-pump unit and permits that unit to be subjected to no more than the static pressure in the tank during periods when the pump is at rest, and this facilitates obtaining effective sealing of the motor assembly.

The pressure dispensing apparatus permits the interconnection of a plurality of systems in a single service station installation. As has been set forth above, the two systems A and B of Fig. I normally operate independently, with the stands of each system supplied with gasoline by the pump and from the tank of that system. In the event of failure of the supply in any system, the stands of that system are readily switched over to control and be supplied from the supply apparatus of the interconnected system. By the use of the modification shown in Fig. 8, that switch-over can be fully automatic in response to the simple turning of the control handle 130, and with the arrangement shown in Fig. l, the switchover requires only the turning of that handle and the opening of the valve 84; and back flow from the Operative system to the tank of the inoperative system is normally prevented by the header check valves, and may be completely cut off by closing the manual valve 23 or 73. While the number of stands which can be operated simultaneously from one pump will be less than the full capacity from two pumps, all stands will be operative, and normal service station operations can continue even though limited to less than the normal maximum of multiple dispensing operations.

We claim:

1. Apparatus for dispensing liquid, comprising a plurality of normally independent dispensing systems each having a storage tank, an electric-motor-operated pressure pump for the storage tank, a pressure line leading from the pump to one or more dispensing stands, and electrical control means operable from a stand for actuating the pump of its system, valved means for interconnecting the said lines of two systems, and means to switch the said control means of one system to disconnect the same from actuating the pump of its own system and connect the same to actuate the pump of the interconnected system in parallel with the control means of said interconnected system.

2. Apparatus for dispensing liquid, comprising a plurality of normally independent dispensing systems each having a storage tank, an electric-motor-operated pressure pump for the storage tank, a pressure line leading from the pump to one or more dispensing stands, a check-valve in the line adjacent the pump to maintain the line full of liquid and prevent back-flow therein, and electrical control means for the pump operable from the stands, valved means for interconnecting the lines of two systems, and means to switch the control means of one system to disconnect the same from actuating the pump of its own system and connect the same to actuate the pump of the interconnected system in parallel with the control means of said interconnected system.

3. Apparatus for dispensing liquid, comprising a plurality of normally independent dispensing systems each having a storage tank, an electric-motor-operated pressure pump for the storage tank, a pressure line leading from the pump to one or more dispensing stands, a checkvalve in the line adjacent the pump to maintain the line full of liquid and prevent back-flow therein, and electrical control means for the pump operable from the stands, means for interconnecting the lines of two systems, and means to switch the control means of one system to disconnect the same from actuating the pump of its own system and connect the same to actuate the putnp of the interconnected system in parallel with the control means of said interconnected system, in which the interconnection means contains a normally closed valve, and means to open said valve in response to said switching of control means.

4. Apparatus for dispensing liquid fuel from a storage tank having a top opening, comprising a valveless impeller pump suspended in said tank through said top opening in position to be submerged by liquid therein, a header above said opening, a valveless pump-discharge conduit leading from the pump to the header, from which liquid may drain back to the tank through the pump, a pressure line from the header to a remote dispensing point and terminating in a dispensing control valve, a checkvalve in the header opening from said conduit-to said pressure line, and an open vent which opens from, the top oi said conduit and discharges to said tank, said checkvalye being biased to normally remain closed against a conduit pressure belbw a predetermined valve-opening pressure, andsaid vent being of sufficient gas-passing capacity to maintain the pressure in said conduit below said opening pressure when said conduit contains gas and being of insuflicient liquid-passing capacity to prevent a valve-opening pressure when said conduit is liquid filled at pump-discharge pressure.

5. Liquid fuel dispensing apparatus as set forth in claim 4, in which said impeller pump is combined in a motor and pump unit comprising an enclosed motor having a projecting motor shaft on which the pump impeller is directly mounted and carried, said unit being mounted in submerged position in the tank with the motor above the pump, and having a pump-discharge passage leading from the pump upward along the motor enclosure in cooling relation therewith.

6. Liquid fuel dispensing apparatus as defined in claim 4. in which the header is mounted a substantial distance above the top of the tank and said valveless pump-discharge conduit extends a similar distance to form a chamber of substantial volume above the maximum normal liquid level of the tank and below said vent, from which chamber liquid normally drains back to the tank when the pump is stopped and which provides a low-pressure chamber to receive liquid initially discharged from the submerged pump during starting thereof.

7. Liquid dispensing apparatus as set forth in claim 4, with the addition of a pressure-relief valve in said header in open inlet communication with said pressure line and in open outlet communication with said vented pumpdischarge conduit.

8. Liquid fuel dispensing apparatus as set forth in claim 4, in which said impeller pump is combined in a motor and pump unit comprising an enclosed motor having a projecting motor shaft on which the pump impeller is directly mounted and carried, said unit being mounted in submerged position in the tank with the motor above the pump, and having a pump-discharge passage leading from the pump upward along the motor, said motor-shaft being sealed from the pump-discharge passage by a labyrinth seal and a rotary contact-seal in series in the leakage path from said passage to the motor enclosure, said path being vented at a point between the two seals, whereby said contact seal is maintained under low pressure condition both during pump operation and while the pump is at rest.

9. Apparatus for dispensing liquid fuel from a buried storage tank having a top opening and a riser secured to the tank about said opening and extending upward to an accessible location, comprising a header adapted to be carried by said riser, a valveless motor and impeller pump unit dependingly carried by said header for suspension through said riser to submerged position in said tank, a valveless pump-discharge conduit from said unit to said header, a header outlet to a pressure line for a remote dispensing-control valve, a spring-closed check-valve in said header and opening from said conduit to said header outlet, said conduit and header forming a pump-discharge column extending above the tank and from which liquid may drain back to the tank through the pump, and a vent which leads from the top of said column to a point of communication with the clearance space between said conduit and riser.

10. Apparatus for dispensing liquid fuel at a service station, comprising a plurality of dispensing systems each having a storage tank with a top opening and provided with dispensing apparatus as defined in claim 19 and each having a plurality of. dispensing stands connected to the pressure line thereof, each stand having an electrical control, the controls at all stands of each system being operable in parallel to actuate the pump of said system and normally inoperable to actuate the pump of any other systems, means for connecting the pressure line of one system to that of another system, and means to switch the controls of said one system to actuate the pump of the other system in parallel with the stand-controls of said other system.

11. Apparatus for dispensing liquid fuel from a storage tank having a top opening, comprising a valveless impeller pump suspended in said tank through said top opening in position to be submerged by liquid therein, a valveless pump-discharge conduit leading from the pump upward through said opening and from which liquid may drain back to the tank through the pump, a pressure line connected to said conduit above the tank to deliver fuel to a remote dispensing control valve, a check-valve controlling flow from said conduit to said pressure line and preventing backflow to the conduit, and vent means to release gas from said conduit, said check-valve being biased to normally closed position, said vent means having sufficient gas-release capacity to maintain the pressure in said conduit below check-valve-opening pressure when said conduit contains gas, and said vent means, in the presence of liquid, exerting suflicient back-pressure to effect fuel delivery flow through said valve from said conduit to said pressure line.

12. Apparatus for dispensing liquid fuel from a storage tank having a top opening, comprising a combined valveless impeller pump and motor unit suspended in said tank through said top opening in position to be submerged by liquid therein, said unit comprising an enclosed motor having a projecting motor shaft on which the pump impeller is directly mounted and carried, with the motor above the pump, and having a pump-discharge passage leading from the pump upward along the motor enclosure in cooling relation therewith, a valveless pump-discharge conduit leading from the pump upward through said tank opening, from which conduit liquid may drain back to the tank through the pump, a pressure line from the conduit to a remote dispensing control valve and communicating with the conduit through a check-valve preventing backfiow to the conduit, and open by-pass vent means from the top of said conduit and in discharge communication with said tank, said check-valve being biased to normally closed position, and said vent being of sutlicient gaspassing capacity to maintain a low pressure in said conduit when said conduit contains gas and being of sufficient limited liquid-by-passing capacity to pass a cooling flow of liquid for the motor when the unit is in operation and the remote dispensing control valve is closed.

13. Apparatus for dispensing liquid fuel from a storage tank having a top opening, comprising a valveless impeller pump suspended in said tank through said top opening in position to be submerged by liquid therein, a valveless pump-discharge conduit leading upward from the pump a substantial distance above said tank and forming a chamber of substantial volume above the maximum normal liquid level of the tank, from which chamber liquid may drain back to the tank through the pump when r the pump is stopped, a pressure line from the conduit to a remote dispensing control valve, a check-valve preventing back-flow from said pressure line to said conduit and biased to normally closed position, and open vent means adjacent the top of said chamber to permit such back drainage and of sutfieient gas-passing capacity to maintain a low pressure in said conduit when the conduit contains gas, whereby said conduit provides a low-pressure chamber to receive liquid initially discharged from the submerged pump during starting thereof.

14. Apparatus for dispensing liquid fuel from a storage tank having a top opening, comprising a combined valveless impeller pump and motor unit suspended in said tank through said top opening in position to be submerged by liquid therein, said unit comprising an enclosed motor having a projecting motor shaft on which the pump impeller is directly mounted and carried, with the motor above the pump, and having a pump-discharge passage leading from the pump upward along the motor, said motor-shaft being sealed from the pump-discharge passage by a labyrinth seal and a rotary contactseal in series in the leakage path from said passage to the motor enclosure, a valveless pump-discharge conduit leading upward from the pump to a point above the tank and from which conduit liquid may drain back to the tank through the pump, a pressure line connected to said conduit through a check-valve preventing backflow from said pressure line to said conduit, a vent communicating with the top of said chamber to permit said buck-draining, and a vent from said leakage path to the tank at a point between said two seals, whereby said contact seal is maintained under low pressure condition both during pump operation and while the pump is at rest.

15. Apparatus for dispensing liquid fuel from a storage tank having a top opening, comprising an impeller pump suspended in said tank through said top opening in position to be submerged by liquid therein, a valveless pump-discharge conduit leading from the pump upward through said opening and in which gas may collect, a pressure line connected to said conduit above the tank to deliver fuel to a remote dispensing control valve, a check-valve controlling flow from said conduit to said pressure line and preventing backflow to the conduit, and vent means to release gas from said conduit, said checkvalve being biased to normally closed position, said vent means having sufficient gas-release capacity to maintain the pressure in said conduit below check-valve-opening pressure when said conduit contains gas, and said vent means, in the presence of liquid, exerting sufficient backpressure to ellect fuel delivery flow through said valve from said conduit to said pressure line.

I 6. Apparatus for dispensing liquid fuel from a buried storage tank having a top opening and a riser secured to the tank about said opening and extending upward to an accessible location, comprising a header adapted to be carried by said riser, a motor and impeller pump unit depcndingly carried by said header for suspension through said riser to submerged position in said tank, a valveless pump-discharge conduit from said unit to said header, a header outlet to a pressure line for a remote dispensingcontrol valve, a spring-closed check-valve in said header and opening from said conduit to said header outlet, said conduit and header forming a pump-discharge column extending above the tank and in which gas may collect, and a vent which leads from the top of said column to a point of communication with the clearance space between said conduit and riser.

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